Improve and simplify docker operations

[zhangchuck]

• [ ] Put environment variables into a YAML and pass to the dockerfile
  • [ ] DISCORD_QUOTEBOT_BUCKET
  • [ ] DISCORD_QUOTEBOT_TOKEN
  • [ ] DISCORD_QUOTEBOT_DB_FILENAME
• [x] Create a docker makefile
• [ ] Integrate docker makefile with webhooks infrastructure (see https://github.com/play4honor/p4h_webhooks/issues/1)
• [ ] Improve the docker makefile so that it can run any version (latest, development, local) instead of hardcoding the commands